Microbiological monitoring of ultrapure dialysis fluid in a hemodialysis center in Alexandria, Egypt

摘要

Microbiological contamination of dialysate is an issue that attracted attention since the 1990s. This is partly due to the extensive use of sodium bicarbonate as a dialysate buffer, which helps microbial proliferation, and also the use of high flux dialysers that allow back filtration of microbial contaminants.1 Microbial contaminants most frequently found in dialysis water are bacteria and their degradation products, such as endotoxins, peptidoglycans and bacterial DNA (bDNA). Fungi, viruses and protozoa can also be encountered occasionally.2 Endotoxins are heat-stable lipopolysaccharides (LPS) and the major cell wall components of Gram-negative bacteria.3 The molecular mass of LPS ranges between 2000 and 20,000 Da. LPS can be transferred through membranes with large pore size by back filtration/diffusion from the dialysis fluid to the blood compartment.4 If the dialyser membrane is tight, bacteria are not able to pass from the dialysate compartment into the blood compartment. However, endotoxins, can permeate and cause an inflammatory state.